Method of weaving ladder tapes



Aug. 8, 1944.

a R. HOLMES yMETHOD OF WEAVING LADDER TAPES originai Filed March 1e, 1942 3 Sheets-Sheet l \NvENToR i ELBFuDGE R Homes .AT-f cuara` AUS 8, 1944- I E. Rf HoLMEs'- i 2,355,532

` METHOD 0F wEAvING LADDER TAPES Original Filed Marh 16, 1942 3 Sheets-Sheet 2` INV EN To R ELBRuDer-z R. HOLMES RNEY.

Aug. 8, 1944.

E Alfa.- HoLMgs METHOD OF WEAVING-.LADDER TAPES :s sheets-sheet s Original Filed March 16, 1942 mvENi-aR ELBRNDGE R HOLMES Patented Aug. 8, 1944 UNITED STATES PATENT lOFFICE Elbridge R. Holmes, Worcester, Mass., assigner to y A Crompton-8; Knowles Loom Works, Worcester, I' Mass.,a corporation of Massachusetts y Original application March l16, 1942, Serial No. 434,920. Divided and this application August.r

24, 194,2, serial YNagaz v Y solaires. (01.,139v22) .v1

This is a division of my co-pending application Serial No. 434,920, led March 16, 19472, for Loom for weaving ladder tapes. This invention relates to improvements inlooms for Weaving ladder tapes such for instance asare utilized to support the cross slats of Venetian window shadesand it is the general object ofthe invention to provide improved means for manipulatin'g the Warp threads which pass from one Web to the other to form the ladder or crossing bars.

Ladder tapes customarily employ two webs which are connected at spaced intervals either b y narrow groups of warp threadsor woven sections. The warp threads which form the crossing bars are Woven into the two webs between crossings, forming part of the sheds of their respective webs. When the point in weaving is reached at which a crossing bar is to be formed, the crossing warps leave the sheds in which they have been previously located and pass tothe opposite web. The two sets of crossing threads cross each other at a point considerably behind the fells of the two webs and cause objectionable loops at the selvage of the Webs at beat-up It is an important object of my present invention to provide an advancing hook or the like for the crossing webs to move them to their extreme forward position prior to beat-up and-preferably ata time in the advance of the lay when-the weft threads will still be under sufficient tension to moveto their respective fells without forming loops. Y 5

. In previous looms for weaving ladder tapes it has been proposed to move the crossingjpwarps forwardly by mechanism connected to the'lay with the result in certain instances that the crossing threadsdo not move to their extreme forward position until after 'the harnesses have started to cross. Any loop which might have been formed at the selvage cannot therefore be straightened because the weft thread is held by' thewarp threads. It is another object.' of 'my present invention toprovide means to advance the crossing warps to their extreme forward'position'prior to closing of the warp sheds and therefore permit the weft tension to straighten the aforesaidloops.` v i The Warp sheds are ordinarily closed at front center but the exact time of closing depends upon the type of harness mechanism employedv and also its setting. The sheds will alwaysl be partly open when the lay is at bottom center and it is a more specific object of my present invention `to `manipulatethe crossing warp advancing means so that it will reach its extreme forward position approximately at the time the lay is at bottom center. This timing insures that the shedswill be open enoughto permit the weft tension to straighten the loops at the selvages;

The warp sheds are suiciently open at top center to permit entry of the shuttles and on crossing beats of the loom ythe crossing warps will f orm a shed wide enough for entry of the advancing hook or the likebefore the lay reaches back center. Y `In'order that the crossing warp advancing means may reach its extreme forward position prior to front center it is a further object of my invention to movethe crossing warp hooks or the like to their`- extreme rearward position at some point in the loom" cycle ybetween top and back centers and thereafter move the hook forwardly before the lay starts to` advance. In this manner Igive vthe crossing'warp advancing hookits complete back andfortli movements in a period considerably lessthan one yfull pick of the loom. 1 TItisa specific object' of Yrny present invention to achieve the last named object by rack and pinion mechanism operatively connected to a transverse bar and effective starting at a point substantially ati front center tor cause the bar to move to its rearward position in a periodsomething less than half a pick and-immediately thereafter move the bar forwardly While the lay is still receding. The driving rack `is 'caused to reciprocate' by cam mechanism similar to that already known and the crossing Warp advancing hook, pivotally mounted on" the bar, is caused to swing laterally away from the' Warp threadsv as" the bar moves rearwardly and then return to-its normal position with respect to the bar behind the crossed warps as the barstarts forwardly; @A further specific object of vmy invention is to provide improved cam means for rocking-'- the crossing warp hooks on the bar during backward motionv of the latter `w`ithout disturbing the hooks as they'inove forwardly. 1My'f Ainvention further relates to an improved method-forl the manipulation of the warps in a l'oom weaving ladder-tapesor the like. The method-consists'essentiallyin the steps of crossing the ladder v- `forming warps, lmovingv their point of crossing forwardly to'cause the crossing warps to lie in' the outside shedsof theground fabrics while the ground sheds are open, exerting tension on the weftthreadsto take'up slack at the selvages and thereby prevent formation of the loops while the ground shedsare open andthereafter closing ythe ground sheds; l

`Withv these and other objects in ,View which will appear as the description proceeds, my inthe crossing warp hook in `the process of being moved to a position behind the crossing warps,v

Fig. 4 is a vertical section on line 4 4 of Fig.

3 on an enlarged scale showing the cam which operates the crossing warp hook,

Fig. 5 is a vertical section on line 5-5 of Fig. 2

on an enlarged scale showing the rack and pinion mechanism for operating the hook carrying bar,

Fig. 6 is a detailed side elevation of a part of the rack and pinion operatingcam shown in the lower part of Fig. 1, but on an enlarged scale,A

Fig. '1 is a rear elevation of the. structure shown in Fig. 6,

Fig. 8 is a composite view showing in perspective parts of the cam mechanism shown in Fig. 4, and

Figs. 9 and 10 are diagrammatic views showing the sheds of the two webs in two different positions.

Much of the structure utilized in my present invention has already been set forth in my prior Patents Nos. 2,025,866 and 2,082,890, and also in my co-pending application Serial No. 396,274 led June 2, 1941, now Patent No. 2,319,863, These patents and the application may beA referred to for certain structures not fully described hereinafter and the following description will be confined to the improvements` repre-.- senting my present invention together withsuch reference tor other loom parts as is deemed necessary. i. -V

Referring to Fig. 1, I have shown a loom frame I!) having a xed breast beam I I and a lay I2 with a reed Rrocking backwardly and forwardly about an'axis I3. The top shaft I4 of the loom may operate through connections designated generally at I5 to cause reciprocation of the lay andY may be geared in any approved manner to thebottom shaft I6. The latter shaft preferably completes one revolution every other pick of the loom and has mounted thereon certain of the mechanis which operates a part of my invention. i

Secured to the bottom shaft I6 is a disk 2li on which is Vmounted for angular adjustment acam 2| which is shown in detail in Figs. 6 land 7. Cam 2| has a web 22 bolted to the disk and having concentric inner walls 23 and outer walls 24.` OppoeA site sides of the cam are provided with runs 25 formed by inner and outerwalls 26 and 21, respectively, which communicate with the concentricrun 28 extending between the walls 23 and 24. In order that the crossing of the ladder forming warps may occur on any pick of the loom the cam is provided with two of the runsv 25 on opposite sides of the shaft I6. Since the runs and associated parts are the same I will describe the one at the left of shaft I6 as seen in Fig. 1.

Run 25 has associated therewith upper and low/erswitches 29 and 30, respectively, mounted on'pivot pins 3| extending through the web 22. The switch has an inner surface 32 which assists in forming the circular path 28 when the switch 7 5;

is in its normal full line position shown, for lnstance, in Fig. 1

A lever 35 is pivoted as at 36 to the loomside and has its rear end provided with a roll 31 which moves in the runs 25 and 23. When the switches are in their normal positions the bottom shaft turns without causing rocking of the lever 35, but when switch 30 moves to the dotted line position shown in Fig. 6 the roll then passes from the run 28 into the run 25 as the cam turns in the direction of arrow a. Movement of the roll 31 in the non-concentric run 25 causes 4lever 35 to rock first in a clockwise and then `3o shan *move from its normal position is ser forth in Fig. '7, wherein it will be seen that a lever 40y is secured to a stub shaft 4| rotatable on a carrier 42 through which the shaft I6 extends. The carrier is held by a bolt and slot connection 43 in adjusted angular fixed positiony on a bracket 44 rsecured to the loomframe. ,Secured tothe stub shaft 4I is an arm 45 theV lowerendof which as seen in Fig. '7 'is provided with a shoe 4 6. A spring 41 normally holds the shoe 46 at one side of the path of a stud secured to a lever SI fastened to the pivot pin 3| of switch 30. A light tension spring 52 normally holdsthe stud 50 yin the position shown in Fig. 7 and also holds the switch 30 in the full line position shown in Fig. 6 to cause roll 31 to move in a circular path. A flexible .connector 54 is attached to the upper end of lever 40 and when this connector 54 Ais raised lever 40 is rocked around its axis against the action of spring 41 to move the shoe 46 into the path of stud 50. This action occurs prior to arrival of the stud to the position shown in, Fig. 'l as the cam rotates. Further rotation of the cam moves the small lever 5I angularly in a right hand direction as viewed in Fig. 7 relatively to the cam and causes shifting of -the switch 30 from the full to the dotted line position of Fig. 6. It is in this way that the roll 31 is caused to leave the circular path 38 and enter the vpath 2 5.

The upper end of connector 54 leads to a pattern mechanism designated herein generally at K. It is not deemed necessary to describe lthe details of ythis mechanism and it is thought sufficient to state that o n those picks when ladder crossings are to be produced the mechanism K operates to raise connector 54 in time to permit engagement of shoe 46 by stud 50. The mechanism K has leading therefroma second connector 55 which leads to a measuring mechanism for the crossing warps designated generally at M; Leading upwardly frommechanism M is a system of links 51 connected as at 58 to a lever 5 9 secured to a rock shaft 60. Arms 6I depending from and secured to shaft carry a bar 6 2unfder which extend the crossing warps designated generally at C. When the loom is to havelalad? der bar forming operation the mechanism K will control the mechanism M, Fig. 1, andthe latter in turn will operate through-linkage;'51torock shaft 60 and move the bar 62 forwardly, or 'ofthe left as viewed in Fig. 1, to supply indiener-ii of yarn of the cross warp C needed to pass from'one to the other of the two webs being .Wovenand'to be described hereinafter. l, e i

As shown in Figs. 9 and 10 I set-forthtdiagrammatically the relation between the various warp threads, the two webs of the 'ladder-:tapa andthe advancer for the cross Warps. Theftp: and

`'bottom fabrics F and FI, respectivelyare formed principally from ground warps dening two sheds, one shed for each fabric. The upper fabric F connects to warp threads Wl and W2 which dene the upper shed for top shuttle SI, while fabric FI isconnected to warp threads W3 and W4 which form the lower shed to receive shuttle S2. The warp threads connect with their respective fabrics at the fells e and the top and bottom sheds always occupy substantially the positions as shown in Figs. 9 and 10 when the shuttles are active. The cross warps C are in two groups, one shown at CI for the top web and the other at C2 for the bottom web, and each group will be woven into the corresponding fabric on non-crossing beats of the loom. On crossing beats, however, the crossing warp C| from the top fabric will extend downwardly andr rearwardly below warps W2 intothe lower shed, While the cross warps C2 will rise and extend rearwardly to a position above warp W3 and into the upper shed. The two `crossing warp groups will cross `each other at b at a point considerably behind the fells e. It will be seen particularly from Fig. 9 that the upper shuttle for instance passes through a shed formed by warps `W2 and the cross warps C2 so that the weft which the shuttle lays will extend from the point d forwardly to the upper fell e. Similarly, thelower shuttle passes through a shed formed by warps W3 and the lowered cross warps C and its weft extends from point d' forwardly to the lower fell. Unless provision is made for advancing the points d and d objectionable loops will be formed on the selvages of the webs F and F.

. The matter thus far described of itself forms no part of my present-.invention except as pointed oui-,hereinafter and may be made as set forth in the previously mentioned patents and copending application.

In carrying my invention into effect Iprovide means for advancing the cross warps C and C from their positionshown in Fig. 9 to cause points d and d to approach or coincide with the fells e.y A shaft 10 is rotatably mounted in bearings 1| on the breast beam and has secured thereto a pinion 12 which meshes with a verticalrack 13 secured to the upper end of a rod 14 the lower end of which is attached as at 15 to the lever 35. The rack is in front of the pinion and is guided by the adjacent bearing 1| to cause rotation of shaft 10 in a clockwise direction as viewed in Fig. 1 when roll 31 enters run 25 and cause v,counter-clockwise rotation of the pinion after the roll has passed the high point of run 25 and approaches a circular run 28.

A bar 80 extends parallel to and behind the shaft 10 and has securedthereto forwardly extending rack bars 8| which are slidably mounted ink bearings 82Y secured to the breast beam Each rack bar 8| meshes with the top of a pinion83 secured to the shaft 10. The rear of each rack bar 8| may be secured to the bar 80 by means of a casting 84 xed to the bar and also to the rack. Thebars 8|- support the bar 80 when the latter is moved backwardly and forwardly and are also the means by whichthe latter motions are communicated to the bar 80.

' It is to be understood thatV theloom to which my invention is applied willbe capable of weaving several ladder tapes as is customary in n arrow ware looms, but in the present instance I set forth mechanism for weaving but one ladder tape. Projecting rearwardly from4 the breast beamandsecured thereto is a guide 86 forked at ear kI .ndfto provide v al horiaontalv slot 01:,

through which the webs F andFl pass. Across-- ing warp finger orhook 188 has the rear beni-,Tend v89 thereof proportioned to move forwardly-inthe slot 81 from a position behind point b shown in Fig. 9. `The hook 88 is secured to -a small lever 90 Vpivoted 'as at 9| to the cross bar.'v A light-tension spring 92 between the bar andthe lever 90 tends normally tomove the latter to the left so that the hook and guide will ordinarily be in the position shown in Fig. 2. Extending along the bar are spaced parallel front and back rods 95 and 96, respectively, which are pivoted as at 91 tothe front and back ends of the lever 90. The 'right ends of rods 95 and 96 are pivoted as at |00and. |0|, respectively, to a lever |02pivoted as at |03 on the bar 80. Lever |02 projects rearwardly and has mounted thereon Va roll |05 which is normally in the position of Fig. 2 atY the frontof a cam slot |06. The latter extendsirearwardly and to the right as at |01 and athen rearwardly as at `|08 and then rearwardly and tothe leftasatl. I i,-.

The slot |05 is defined by right'. and left -walls |I0 and lil, respectively. ,Wallf Il() hangs downwardly from a plate ||2 secured" -to the breast beam by means .of abolt ||3 ,which passes through a saddle H5 bolted as at ||1 to the breast beam. Bolt I3 passes through abackwardly and forwardly extending slo-t ||8 in `.the plate v| |2 which affords adjustment of slotf|06 towardand from roll |05. A rib |20 onthe lower forward face of plate H2, see'Fig.I 8, fits into a groove |2| in the saddle and serves to po. sition the plate |I2 and hold the samein xed position as shown in Figs. 2 and 3. 1 i

The wall Ill is formed on a pivot tongue4 |25 the forward part of which has va bearing |26 to receive a pin |21 mounted in depending lugs |28 on the bottom of platel |2. The tongue |25flts in ahslot |30 .extending rearwardly in plate Y| |2 and a rear supporting lug |3| on the tongue overhangs the plate ||2 at the end of the slot v|30 to hold .the tongue normally in thedown .posi tion shown in full lines in Fig. 4. The wall isformed as part of a head |35 on the underside of the tongue and the rear part of the head has a forwardly and downwardly inclined surface |36. A shock absorbing `cushion |40 carried by the breast beam isl positioned Ifor. engagement with the bar 80-when the latterreaches its Aextreme forward position. .1

r Under normal conditions when the loom` is Weaving between cross or ladder bars ofthe cross warps the parts will be in the position shownin Fig. 2 and lever 35 will ybestationary:with-the switch 30 in position to causerthe roll 31fto move in acircular path. When thelmechanism K determines that the crossing warps C shall assume theposition .shown in Fig. 9 forthe purpose of forming a ladder bar L, the switch'35 will be thrown to the dotted line position of Fig. -6 as already described, whereupon rod 14 will-rise to cause rotation of shaft 10 and rearward movement ofthe rackY bars 8| and bar 80. 'The start of the rearward motion of the bar 80` will ordinarily occur when the lay is at -front center and when the roll |05 is'at the forward end of slot |06. As the bar 80 moves' rearwardlyV the roll |05 moves along part |01 of the slot |06, thereby rockin-g lever |02 to the right, see Fig. y.5 to cause rods 95'and 96 to move, respectively', to the left and vright to rock lever from `the positionv vof Fig. 2 tothe full linepositionof Fig. 3l a y Asthe bar 80 continues to move rearwardly`r the $0.11!" .Slidestlirllgh the .Sireishtse'tion ,1.9i

of slot |08 to hold the hook88 in the angular position shown in full lines in Fig. 3 with the left end -of the hooked end 89 to the right of the warp threads. As the bar 80 approaches the endof its rearward movement roll |05 is moved to the left by section |09 of slot |05 and lever 90 assumes the position shown in dotted linesin Fig. 3 to cause the end 89 to move into the warp shed defined by the crossed threads C`| andCZ to a position behind point b, Fig. 9.

The run of cam 2| is so proportioned that the bar 80 will reach its rearmost position and hook 88 will be in the dotted line position shown in Fig. 3 when the lay is approximately half way between top and back center positions. At this time the sheds are sufficiently open to Ypermit entry of the hook 89 behind the cross warps. As cam 2| continues to rotate roll 31 moves toward circular run 28 and rod 1.4 starts to move down, whereupon the bar 80 will begin its forward movement. As soon as roll |05 engages the inclined surface |36 the tongue |25 will be raised and swing around its pivot pin |21 to the dotted line position of Fig. 4, the spring 92 holding the lever |02 and parts connected thereto fixed with respect to bar 80 in the dotted line position shown in Fig. 3 throughout the entire forward motion of the bar 80. After the roll |05 is moved to a position in front of the head the tongue falls to its normal position. The forward motion of the bar and therefore of the hook 88 is completed while the lay is still some distance from front center but on its forward beat. I preferably complete the forward motion of the hook when the lay is about at bottom center position.

Upon completion of forward motion of the bar 80 the warp threads and the crossing warp hook will be in some such position as set forth diagrammatically in Fig. 10. In that figure it will be seen that the hook end 89 has moved to a position in front of the fells e and has caused the cross warps CI and C2 to lie near the warp threads W4 and Wl, respectively. Thus, the group of threads CI from the top web F extend downwardly and forwardly from their correspending fell e, in front of the hooked end 89 and then downwardly and rearwardly along a path which lies close to the fell of the lower fabric Fl. The lling or weft thread G can therefore be beaten forwardly to the fell without the formation of loops.

In order that the weft threads G may be under tension to take-up slack in them as points d and d advance, I preferably time the movement of the shuttles so that the latter are still moving when the hooked end 89 reaches its extreme forward position. Fig. 1 shows shuttle operating racks for manipulating the top and bottom shuttles SI and S2. These racks are connected to the usual operating mechanism which keeps them in motion preferably until bar 30 returns to its extreme forward position. It is not essential that the movement` of `the rack bars |45 shall have any precise timing relationship with the bar 80 so long as a pull is exerted by the shuttles on the weft threads G to take up any slackness which might otherwise form loops at the selvage. Thus, the bar |45 may if desired continue its motion after the bar 80 has reached its foremost position, or if desired the rack bars |45 may cease moving shortly before bar 80 is fully forward and reliance may be placed upon the thread tension customarily found in narrow ware shuttles. In any event it will be desirable to provide some means to take up slack in the weftv prior tothe crossing yof the harnesses H.

Whatever the method employed for maintaining tension .on the weft thread as the hooked end 89 moves forwardly, it is important to complete the movement of the -hooked end 89 to its forward position so that point d will lie adjacent Yto the fells e .before the warp shedsare closed sufliciently to resist movement of the weft threads.

Patents Nos. 351,259 and 613,974 maybe referred to for shuttles of the type which are provided with weft slack take-ups the effect of which is to create tension in the weft after the shuttles come to rest. My prior Patent No. 1,817,146 may be referred to for a type of mechanism forimoving the rack bar |45 to operate the banks of shuttles.

From the foregoing it will be seen that I have provided means for :moving the point of crossing of the cross warps CI and C2 forwardly so that the cross warps will lie close to the fellsiof -the two webs while the warp sheds are open wide enough to permit the weft tension to tighten the weft threads and thus prevent the formation of loc-ps. It will be vseen that this result is accomplished by nio-ving the bar rearwardly and forwardly during a period of time substantially less than one pick of the loom, preferably from front center position of the lay to the following bottom center position. It will further be noted thatfthe hook 88 is moved by a mechanism independent of .the .lay which permits the hookk to reach its extreme forward position before the lay reaches front center, More specifically it will be seen that I have provided a rack and pinion system of driving gear for the bar 80 whereby movementof lever 35 connected to the system effects rst a lrearward and then a forward motion of the hook 88 by means of a cam switch. -It is to be understood that the run 25 of the cam120 is made of such angular length as to cause the movements of the bar 80 already described. Also, the cam which controls the roll |05 has a pivoted tongue which assists in causing rocking of the hook 88 during backward motion of the bar 80 but permits the hook to remain substantially at rest with respect to the bar 80 when the latter is advancing. While I have shown two rodsand 96 I do not wish necessarily t0 be limited to the use of both ofthem. It will also vbe 'seen that 'I have provided an improved method for the manipulation of the ground and crossing warps whereinthe crossing warps are caused to coincide with certain sheets of the ground warp sheds before the latter are closed to permit the weft to be drawn tightly to prevent the formation of loops at the selvage, after which "the ground sheds are changed.

This application is va division of my prior application Serial No. 434,920 in which the novel structure set forth hereinbefore is claimed. The present applicationV is` restricted to the method of weaving ladder tapes set forthin the preceding description. y

Having thus described my invention it will be Vseen that Ychanges and modifications may be made therein by those skilled in the art without departingfrom the spirit and scope of the invention and I do not wishto` be limited to the details herein disclosed, but.what I claim is:

A1.*'Iheinethod offorming cross bars in ladder tape in a loom having two ground sheds one oveiI the ,other `and a set of crossing warps to form the cross bars, said method consisting of the following steps: crossing a group of crossing warps from one ground shed to the other ground shed, passing a weft from the fell of said other shed through the latter and behind the crossing warps, completing forward movement of the crossing warps to locate them adjacent to the fell of said other shed while the latter is open and thereafter closing said sheds and beating the weft to the corresponding fell.

2. The method of forming cross bars in ladder tape in a loom having two ground sheds one over the other and a set of crossing warps to form the cross bars, said method consisting of the following steps: moving the set of crossing warps from one shed to the other shed, passing weft under tension from the fell of said other shed through the latter and behind the crossing warps, completing forward movement of the crossing Warps to cause them to lie along the fell of said other shed prior to beat-up and while said other shed is still open, and thereafter closing said other shed and beating the weft to the fell of said other shed,

3. The method of forming cross bars in ladder tape in a loom having two ground Sheds one over the other and a shuttle having weft connected to the fell of one of said sheds and a set of crossing warps to form cross bars, said method consisting of the following steps: moving the set of crossing warps from the other shed to said one shed, moving said shuttle to cause the same to pass through said one shed to lay weft behind the crossing warps, completing forward movement of the crossing warps to cause them to lie along the fell of said one shed while the shuttle is still moving and prior to beat-up and while said one shed is still open, and thereafter closing said one shed and beating the weft laid by the shuttle to the fell 0f said one shed.

4. The method of forming cross bars in ladder tape in a loom having two ground sheds one over the other and a shuttle having weft connected to the fell of one of said sheds and a set of crossing warps to form cross bars, said method consisting of the following steps: moving the set of crossing warps from the other shed to said one shed, passing a shuttle through said one shed to lay in the latter the thread connected to the fell of said one shed behind the crossing warps, completing forward movement of the crossing warps to locate them at the fell of said one shed prior to completion of movement of said shuttle while said one shed is open, and thereafter beating the weft against said crossing warps at said fell and closing said one shed.

5. The method of forming cross bars in ladder tape in a loom having two ground sheds one over the other through which shuttles pass to lay weft and a set of crossing warps to form the cross bars, said method consisting of the following steps: moving the set of crossing warps from one shed to the other shed, passing weft under tension from the fell of said other shed through the latter and behind the crossing warps, completing forward movement of the crossing warps to cause them to lie close to the fell of said other shed while the latter is still open, and thereafter beating the weft against said crossing warps at said fell and closing said other shed.

ELBRIDGE R. HOLMES. 

